TV Installation Basics
An Overview Of Installation Techniques,
Tips and Frequently Asked Questions
Started - The Site Survey
A Written Installation Agreement
Word About Focal Depth
Noise Block Amplifiers - The LNB
Actuator Arm - The Dish Mover
Step - Installing The 4DTV IRD
Started - The Site Survey
The Site Survey is the first step in a good installation. The
purpose of the site survey is to assure that several conditions
are met that will insure the proper operation of the C-Band TV
system. The conditions you are examining are;
Is there and unobstructed view to all of the satellite
Will seasonal foliage cause problems?
Is the area that the dish is to be anchored in solid?
Is the area aesthetically acceptable to the purchaser?
Are there sources of terrestrial interference that need to be
Use of a precision tool like the Gourmet Entertaining Sat-Site
will expedite your site survey. Make sure to invite your client to
help with the survey. Allow the client to use the Sat-Site and
find an acceptable location - this always helps to build
excitement and eliminate misunderstanding.
You must verify that there are no transmissions in the 3.7 to
4.2 GHz frequency band that will cause problems with reception. An
easy way to verify this is to use a good LNB, connected to a
signal strength meter and no dish. Sweep the LNB around the target
area in a full circle. If the LNB picks up spikes of signal it is
safe to assume those same spikes may cause interference in the
finished installation. Call your local phone company's engineering
department to verify there are no transmitting towers in the
Use A Written Installation
This can't be stressed strongly enough. Use a written agreement
to verify pricing, location and costs before you begin
work. An agreement, signed by both the contractor and the client
will help to alleviate future problems and assure that all parties
understand exactly what the terms, conditions and issues
pertaining to the installation are. This is a good practice for
both the dealer and the consumer ñ it avoids miscommunications.
Planting The Dish
A properly installed dish requires a perfectly plumb, well
anchored solid base. A good idea is to fill the pole with concrete
as well as pouring a concrete base, this will further strengthen
and stiffen the installation allowing for more accurate reception
of C and Ku band signals.
- Check For Plumb in Three Directions.
- Allow the Concrete to Harden for 24 Hours
Before Mounting the Dish
- Use Braces Welded or Drilled Through the Pole to
Prevent Turning in the Concrete Under Load Conditions
A good "rule of thumb" is to use one bag of concrete for
each full foot of dish size. A seven and one half foot dish should
have seven bags of concrete as an anchor for a minimum. More is a
good idea if you are in a region where strong storms are common.
Every dish sold comes with directions for assembly. Make sure
you read the instructions before attempting to assemble the dish!
Some important things to remember;
- The dish needs to be perfectly shaped. Use a measuring tape
and measure across the diameter of the dish in three
directions. All measurements should be identical.
- Tie a piece of string across the diameter of the dish in two
directions. The strings should just barely touch at the center
of the dish. If the strings are pushed hard against each other
or fail to touch then the dish is not properly assembled.
- Don't over tighten the dish mounting hardware. You do not
want the ribs to be deformed by pressure as this will prevent
proper alignment. Allow the lock washers to perform the job of
securing the bolts.
Mounting The Feedhorn
Contrary to popular belief, the dish is not the antenna.
It is a reflector that focuses the energy into a small golf-ball
sized orb at the mouth of the feedhorn. Inside the feedhorn is a
small probe that is turned by the servo motor to select vertical
or horizontal polarity. This probe is the actual antenna. Knowing
this will allow you to see how important it is to properly mount
Do not assume, as so many do, that because all the supports
holding the scalar ring are the same length that centering is
automatic. You need to assure that the scalar ring (the supporting
ring for the feedhorn) is parallel to the bottom of the dish and
that it is perfectly centered in the dish. Failure to assure this
step will cause imperfect reception. Having the focal point of by
as little as one half of one inch can cause a fifty percent loss
in signal strength!
Measure from the edge of the dish to the scalar ring in at
least three directions to assure that it is centered. Each
measurement should be within 1/32 inch of the other measurements.
Accuracy here will reward you with better performance later.
A Word About Focal Depth
The f/D ratio is the focal distance of the dish (f), divided by
the diameter (D). When dealing with most prime focus antennas, the
number should come out between .28 and .42. If you notice, most of
those numbers are also on scale on the side of the feedhorn. You
simply set the top edge of the scalar ring even with the line that
corresponds to your correct f/D setting. What this adjustment
actually does is determines how wide of an angle the feedhorn can
To calculate the focal distance, you have to measure the
diameter (D) and the depth (d) of the dish. Measurements should be
in like units (you can't use feet for the
diameter and inches for depth). For the example, let's say we have
a dish that is 120 inches in diameter (D) and 18 inches deep (d).
Focal distance (f) equals the diameter squared (D x D) divided by
16 times the depth (16 x d) or :
After you have calculated the focal distance (f), you can use
that figure to calculate the f/D ratio of your dish. In this case,
using the same diameter of (D) = 120; and the calculated focal
distance (f) = 50
f / D = 50 / 120 = .416
f /D = .416
You would round up to give a setting of .42.
All of this information will be provided in the dish
manufacturers instructions so it is important to read the
directions and understand the type of equipment you are working
with. Often times you will be working on a system that was
previously installed. Knowing how to calculate these settings will
make troubleshooting and setting up an unfamiliar dish much
Moisture is the enemy of microwave reception so making sure the
feedhorn and LNB's are protected and properly installed is very
important to long-term service free performance of a C-Band TV
Make sure that all coaxial cable connections are crimped with a
proper tool and treated to prevent moisture from entering the
cable. Make sure you use the gaskets supplied with the LNB's to
prevent moisture from entering the throat of the feedhorn. Also,
check to be sure the plastic covering for the throat of the
feedhorn is attached firmly to prevent both moisture and pests
from entering the waveguide.
The diagram below will point out some sensitive areas you need
to check to assure best performance.
Low Noise Block Amplifiers
- The LNB
The LNB is the electronic device that mounts on the feedhorn
and converts that golf ball sized globe of RF energy into an
electrical signal the IRD (receiver) can understand and use. There
are several kinds of LNB. There are LNBF's which use voltage on
the coaxial cable to switch from vertical to horizontal polarity.
There are consumer grade LNB's that use an external servo motor to
turn the probe and select polarity. Last there are Digital
or PLL (Phase Locked Loop) LNB's that are normally used on
commercial installations. It is highly recommended that a PLL LNB
be used on any high-quality TVRO installation whether consumer or
The biggest difference between a normal LNB and a PLL LNB is
the amount of frequency drift. The following charts from CalAmp show the difference in drift between and consumer and
commercial PLL LNB.
No matter the type of LNB, don't get caught up in a numbers
war. Many beginning installer think that a lower temperature LNB
will always be better than a higher temperature LNB. This
is not necessarily true. A PLL 25 degree LNB will almost always
outperform a 17 degree consumer (standard grade) LNB.
Also, you cannot make up for poor dish alignment or
installation with a better LNB or line amplifier. The dish
needs to collect the signal and send it cleanly to the throat of
the feedhorn. All the electronics in the world cannot help the
picture if you are losing half your signal and sending loads of
noise into the feedhorn. Use a good LNB, preferably a PLL LNB -
but spend your time making sure the mechanics of the dish are up
to snuff first.
The Actuator Arm (The Dish
Now that we have the proper LNB mounted on the feedhorn, the
feedhorn mounted on the dish and centered exactly, and the dish
mounted on a plumb and properly secure pole we are ready to
connect the actuator arm. Make sure you use an actuator that is
properly rated for the dish it is attached to. You should never
use an 18" actuator arm to try and move a solid twelve foot
dish! It may work for a while but the chances are good that you
will be replacing it in short order. Try to get the best heavy
duty actuator arm you can - it will pay for itself many times over
in years of trouble free service.
There are two types of actuator, the horizon-to-horizon mount
which allows 180 degrees of uninterrupted travel and the linear
actuator. The linear arm is far and away the most common and will
work just fine in almost all domestic installations. If you have a
desire to view some of the programming on the AOR (Atlantic Ocean
Region) international satellites or the corresponding Pacific
Region birds then by all means try to get a horizon-to-horizon
Rear view of a typical
Rear view of a typical
Linear Actuator Arm.
This arm is set up for
Linear West Use.
A common error made by both new installers and old timers alike
is in attaching the linear actuator arm. East of the Mississippi
we use a Linear West setting. This seems counter-intuitive at
first but closer examination will reveal the sense of this set-up.
We want the actuator arm to push the dish into position and
let gravity help to return it. From the eastern part of the
country the lowest satellites will be on the western side of the
arc so we position the actuator arm on the west side of the dish
(on the right when looking at the dish from behind). From the
western part of the country the situation is reversed and the
lowest satellites will be the eastern birds. West of the
Mississippi we attach the actuator arm to the left of the dish and
call it a linear east mount.
Correct choice of linear east or west will increase the useful
life of the actuator arm. More importantly, on very sophisticated
IRD's like the General Instruments 4DTV, the receiver actually
uses the pulses from the reed sensor switch to predict where a
satellite should be. Misidentifying the type of actuator (calling
it linear east when it is, in fact, linear west) is the most
common problem in using an auto-installation feature like the one
on the 4DTV.
Aligning The Dish
Now we come to the hardest part of the installation, but if we
do our job well and pay attention in the preceding procedures this
will go a lot quicker. The use of a specialized tool like the
Gourmet Entertaining Arc-Set is highly recommended for best
First you need to calculate the declination figure for the
exact area where you are setting up the dish. Declination angles
are extremely important and need to be precise within one-tenth of
one degree for good tracing of the satellite arc, especially for
Ku reception. Remember, we are going to be capturing the signals
sent out by a satellite that is operating with about the same
amount of power as a strong camp lantern, yet it is 23,500 miles
away in space! Attention to detail is the key. Once the
declination offset is adjusted it is not touched again, all
"tweaking" should be done with the polar axis and the
Determine the latitude of your installation by using a map and
then use one of the many declination tables available on the
Internet. Chaparral has an excellent document detailing the set-up
on their info-fax system. Once you know the latitude of your
installation site and the declination angle you can determine the
declination setting mathematically. (Gourmet Entertaining makes
all these calculations for you on the excellent Arc-Set. Call
213-666-2728 for more information).
Once the declination is properly set the procedure is to set
the dish to true south (not magnetic south, you need to
compensate) and use the elevation adjustment to capture the
southernmost satellite visible from your location. This is called
the zenith satellite. Once you are peaked at the
southernmost satellite you use the actuator control on the
receiver to move the dish to the lowest satellite off the horizon
you can see. This is called the extreme satellite.
Once you have located the extreme satellite gently push up and
down on the edge of the dish to see which direction helps clear up
the picture. If pushing down on the lip of the dish clears
up the picture then you need to rotate the polar mount
counterclockwise. If pushing up on the lip of the dish
clears up the picture then you need to rotate the polar mount
clockwise on the pole.
After you have made the azimuth adjustment you then return the
dish to the southernmost satellite and use the elevation
adjustment to clear the picture up. Keep bouncing back and forth
between the extreme satellite and the zenith satellite using the
polar adjustment and the elevation adjustment respectively until
the dish tracks the arc. The attached sheet "Tracking
Problems" will graphically show you the root cause of poor
Last Step, Installing the
The following instructions are based on installing a 4DTV IRD
into an existing system. The only difference between a new system
and an upgrade is the need to align the dish (above) and set the
physical limits of the actuator. Other than that all directions
are very similar.
disconnecting old unit, position the dish to G9-7. Connect
power and dish cables to the new unit.
2) Press <Options 6 4 2> Select actuator and
LNB type. Select "standard" feedhorn.
3) Press <go back>
4) Press<3> to get to the east/west limits
screen. Press <3> to get to the Program Satellites
screen. You may begin programming satellites w/o
programming limits. You may then go back and put the
limits in once you know where the satellites are.
WARNING: Programming satellites without setting the
limits may cause damage to the dish, actuator, roof, etc.
if your system does not have limit settings properly set
at the dish.
6) By using the arrow keys position the yellow
cursor over the G9 tile. Press <enter>.
7) This is the Satellite Adjustment screen. Channel
up to "target" channel of the program you intend
to find to identify the satellite you are on. (Channel 3
is a analog clear, easily identifiable channel)
8) Press <2> for dish position control.
9) Use east or west arrows to move the dish until
you locate the desired signal. The dish should already be
on G9 if it was left at the position before installation.
If unable to locate G9 and only finding opposite format
satellites, you must switch the feedhorn setting to
rotated 90' in step #2 and begin again.
10) Once you have found the correct
"target" channel on the selected satellite,
adjust the dish position to maximize quality.
11) Press <4> for Skew Adjust. Adjust the
skew to maximize quality. You may choose to use the auto
skew feature by pressing <5>. You need to peak skew
on both an odd channel and an even channel. The skew
settings should be 90 degrees apart (if odd is -30 then
even should be +60 for example).
12) Press <go back>and <enter> to save
settings. This will put you back on the satellite chart to
select the next bird to be programmed in. Do NOT continue
yet. Press <view>. Change channel to 7.
13) Press <option>. At the bottom of the
screen you should notice the number in the box marked
"Channels" increasing. Once the unit has stopped
counting (currently there are about 2600 channels) it has
completed downloading the channel maps.
14) While you are on G9-7, take a moment to call a
4DTV ready Program Provider to get the IPG authorized.
They will need the Digital UA# in order to authorize. This
# can be found on the same system status screen on line #
A. Hit options, then 6, then 5 and read the numbers next
15) Resume programming satellites by pressing
<option> and <3>. Select the next satellite
until you have programmed the satellites that you desire.
We recommend manually programming at least 3 satellites in
the middle of the arc and the furthest East and West
satellite. After you have done this you can begin using
the auto dish positioner. Press<1> instead of
<2> as listed in Step 8. This forces the unit to
automatically calculate the location of your selection and
move the dish for you to its "best guess".
16) When programming the "fringe"
satellites or the farthest East/West, make a note to
yourself of the dish position. This will allow you to set
the limits effortlessly. After installing the satellites
press <Go Back> until you come back to the East/West
Limit screen. Press <1> to select E limit. Using E/W
arrows change the numbers to those that you have noted for
the E limit. Press <2> for W limit and do the same
thing. Simply set the limits to a few counts above or
below the satellite locations for C1 and G6. Press
<view> to exit screen.
*Special Steps Pertaining to Acquisition of Digital
17) Some additional skew adjustments may be
necessary to receive digital signals as they are more
sensitive to cross polarization. This can be achieved by
going to the satellite needing adjustment. Tune to either
the 'home' channel or the 'virtual' channel. Press
<options 6 4 4> The highlight should be over the
current satellite location. Press <enter>.
18) You will notice at the bottom of the screen a
box unique to digital channels labeled
This number must be at least 25 to receive digital video.
Play with <2> dish position and <4> skew in
small increments to achieve the highest quality. Channel
to the opposite polarity if applicable and repeat. Press
<go back> and <enter> to save. The opposite
polarity on a digital channel is not always the next
channel in series, it may be several digital virtual
channels higher or lower before the polarities change.
The installation is complete.
4DTV, DigiCipher, DigiCipher II, and DigiCipher II Plus
are registered trademarks of General Instrument All other
product and service names are trademarks of their
respective manufacturers or providers.